CVE-2021-47100

System crash via deferred IPMI device cleanup

Published Mar 4, 2024 · Updated May 11, 2026

Use-after-free in Linux kernel IPMI message handling from 4.15 allows local users to crash the system during module removal. Deferred cleanup_bmc_work accesses bmc_device_type after ipmi_msghandler module removal has freed the module memory containing that device-type object. Reaching the fault requires privileged removal of the ipmi_si and ipmi_msghandler modules while BMC cleanup remains queued, and the demonstrated consequence is a kernel crash.

CVSS severity5.5
Medium
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Linux kernel IPMI message handling from 4.15 allows local users to crash the system during module removal. Deferred cleanup_bmc_work accesses bmc_device_type after ipmi_msghandler module removal has freed the module memory containing that device-type object. Reaching the fault requires privileged removal of the ipmi_si and ipmi_msghandler modules while BMC cleanup remains queued, and the demonstrated consequence is a kernel crash.

The record

CVE
CVE-2021-47100
Published
Mar 4, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-416, T1499
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Mar 4, 2024CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.15
  2. Affected versionversion=b2cfd8ab4add53c2070367bfee2f5b738f51698d <6809da5185141e61401da5b01896b79a4deed1ad
  3. Affected versionversion=b2cfd8ab4add53c2070367bfee2f5b738f51698d <6b3f7e4b10f343f05b5fb513b07a9168fbf1172e
  4. Affected versionversion=b2cfd8ab4add53c2070367bfee2f5b738f51698d <925229d552724e1bba1abf01d3a0b1318539b012
  5. Affected versionversion=b2cfd8ab4add53c2070367bfee2f5b738f51698d <992649b8b16843d27eb39ceea5f9cf85ffb50a18
  6. Affected versionversion=b2cfd8ab4add53c2070367bfee2f5b738f51698d <ffb76a86f8096a8206be03b14adda6092e18e275

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=4.15; version=b2cfd8ab4add53c2070367bfee2f5b738f51698d <6809da5185141e61401da5b01896b79a4deed1ad; version=b2cfd8ab4add53c2070367bfee2f5b738f51698d <6b3f7e4b10f343f05b5fb513b07a9168fbf1172e; version=b2cfd8ab4add53c2070367bfee2f5b738f51698d <925229d552724e1bba1abf01d3a0b1318539b012; version=b2cfd8ab4add53c2070367bfee2f5b738f51698d <992649b8b16843d27eb39ceea5f9cf85ffb50a18; version=b2cfd8ab4add53c2070367bfee2f5b738f51698d <ffb76a86f8096a8206be03b14adda6092e18e275

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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